Long thumb extender

The extensor thumb muscle is a deep muscle in the posterior region of the forearm.

Located in a medial position with respect to the long abductor muscle of the thumb, it originates from the middle third of the dorsal face of the ulna and from the interosseous membrane.

With his insertion tendon he crosses the 3rd dorsal carpal ligament duct and inserts himself at the base of the distal phalanx of the thumb.

With its action, using the dorsal radium tubercle as fulcrum, it extends and abducts the thumb. It also flexes dorsally and abducts the hand radially.

It is innervated by the deep branch of the radial nerve (C7-C8), is sprinkled by the posterior interosseous artery.